1. Field of the Invention
Embodiments of the present invention generally relate to digital microscopy and, more specifically, to a method and apparatus for compressing Z-stack digital microscopy images.
2. Description of the Related Art
A digital microscope images a specimen at different depths to create a sequence of digital images. Each image represents a portion of the specimen at a particular depth of focus. Thus, at a certain depth, only a fraction of the entire specimen is in focus. The sequence of digital images is stacked along a Z dimension corresponding to depth, referred to as a Z-stack. Each image in a Z-stack is focused at a different depth in the captured specimen. The optics of digital microscopes impose a very narrow depth of field, too small to capture the entire specimen in focus with a single picture. Thus, all images in the Z-stack are of the same specimen, but with different focus for each image.
Z-stacks are generally large sized data sets with high resolution, which impose high bandwidth requirements for the storage or transmission of the Z-stack. For example, in several applications, the number of images is 15, 30, or 50, each with a spatial resolution of approximately 100,000 pixels by 100,000 pixels, which imposes high bandwidth requirements for the storage or transmission of Z-stack.
According to some conventional methods for compressing a Z-stack, the digital images in the Z-stack are compressed individually. While simple to implement, such methods for compressing a Z-stack result in large data files. Due to the large size of data files, there are delays in viewing the Z-stack over a bandwidth -constrained (or bandwidth limited) channel. Video compression techniques are also utilized in the field, however video compression delays viewing of the data due to frame-by-frame representation of the Z-stack images.
Thus, there is a need for method and apparatus for compressing a Z-stack of microscopy images.